Electric furnace



Dec. 11, 1923.

T. A. REID ELECTRIC FURNACE Filed Feb. 25, 1922 R a m MA l@ m m WITNESSES: @255% `ATTORNEY f/YM' Patented Dec. 11,-1923.l

UNITED STATES.

PATENT OFFICE.

THOMAS A. REID, OF WILKINSBURG,`PENNSYLVANIA, ASSIGNOR TO WESTINGHOUSE ELECTRIC & MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA.

ELECTRIC FURNACE.

vApplication filed February 23, 1922. Serial No. 538,543.`

To all inkom t may concern.'

Be it known that I, THOMAS A. REID, a citizen of the United States, and a resident of `Wilkinsburg, in the county of Allegheny and State of Pennsylvania', have invented a new and useful Improvement in Electric Furnaces, of which the following is a specification. l

My invention relates to electric furnaces and particularly to electric-resistance furnaces, and it has for one of its objects to provide a relatively .simple furnace construction for electric-resistance furnaces.

A nother object of my invention is to provide a relatively simple and inexpensive means for interlocking a plurality of thin refractory plates constituting the mutlie of the furnace, to prevent relative movement thereof during the operation of the furnace, while permitting the quick removal of the refractory plates whenever necessary.

In practising my invention, I provide a furnace chamber defined by a plurality of spaced Walls of refractory material, with a plurality of thin refractory plates, serving as the muffle or lining of the furnace and also as a resistor-supporting means, and I provide a plurality of refractory members, of substantially Z-shape in lateral crossau Section, for interlocking` with the edge portions of the thin refractory plates to maintain them in their proper operative positions in the furnace chamber.

In the single sheet of drawings,

:i5 Figure 1 is a View, in vertical lateral cross-section, of an electric-resistance furnace comprising the device embodying my invention Fig. 2 is a view, in horizontal lateral cross-section, of a pit-type electric-resistance furnace comprising the device embodying my invention;

Fig. 8 is a fragmentary top plan view of a heating element employed in my electricresistance furnace, and

Fig. 4 is a view, in perspective, of a member of Z-shape embodying lmy invention.

An electric-resistance furnace 11 comprises an outer metallic casing 12 having a plurality of supporting members 13 suitably secured thereto. An outer lining 13 comprises a plurality of bricks or blocks of any suitable heat-insulating material located within the metallic casing 12. An inner lining 14 comprises a plurality of ojierativelv associated.

A plurality of relatively thinrefractory -plates 16 comprise the mutlie or lining of the furnace chamber. each of the plates 16 being substantially rectangular in contour and having a plurality of relatively small spaced-apart, alined, integral projections 1T on one surface thereof. That surface, of the plate upon which are located the projections 1T is so placed as t face the inner lining .11 in order that the relatively smoothsurface of the plates 16 may be immediately adjacent to the chamber 15.

A. resistor member 18 comprises a rod or bar of a suitable metallic material preformed to comprise a plurality of substantially paralicl-extending endeconnected convolutions. substantially as illustrated in Fig. 3 of the drawing. The resistor member 18 operatively engages the surface of the plates 16 with the convolutions of the resistor member extending between the adjacent rows of alined projections 17. The plate 16 and the resistor member 18 constitute the heating element of my electric furnace and are more particularly described and claimed in application Serial No. 449,685, filed March 5, 1921, bv O. A. Colby and myself and assigned to `the lVestinghouse Electric andManufacturing Company. In that application, the plates 1G are illustrated as being provided with'cdge portions having a groove thereon to provide, in effect, a shoulder near the edge portions of the plates. As the plate is relatively thin, there is a possibility of a breakage of the edge portions of the plates and a possible interruption of the operation of` the furnace consequent thereto. I have found it desirable to so change the edge portions of the plates as to do away with the shoulder and to employ in place thereof, a securing or locking means now to be described.

A thin metallic or refractory member 19., of substantially Z-shape in lateral crosssection and substantially coextensive with llt) the length of the refractory plate with which it is to be operatively associated, is placed between the adjacent portions of each two plates 16, substantially as illustrated in Fig. 1 of the drawing. In this position,

the end surface and an adjacent edge porof, after which the two side plates 16 mayv be'placed in their proper operative positions. rltwo members 19 mayv then befplaced upon the side plates 16 in substantially the positions illustrated in Fig. 1, after which the top plate 16 may be placed in position, it being understood that resistor members 18 are located in their proper operative positions on each of the respective plates 16 before they are movedlongitudinally of ther Vfurnace structure into their respective operative positions in the furnace chamber.

In Fig. 2 is illustrated a pit-type of Ifurnace in which the'furnace chamber 15 eX- tendsvsubstantially vertically. The furnace casing 12, the outer lining 13 and the inner linmg 14 may be of substantially the same material as hereinbefore described in connection with the horizontal furnace illustrated in Fig. 1 of the drawing. As the thin refractory plates 16 now extend substantially vertically, the interlocking members 19 may be symmetrically placed with reference to the adjacent plates 16, as any one of the plates 16 may be first,.placed in its proper operative position in the furnace structure and the vother plates 16 placed in their proper operative positions in sequence around the furnace chamber. I Vhile no supporting structure has been shown or indicated in Fig. 2 of the drawing, any suitable or required construction may be employed in any manner well known inthe a Thedevice embodying my invention thus lprovides a relatively simple and inexpensive means for so interlocking the adjacent edges of relatively thin refractory resistor-supporting plates as to maintain them in their `proper operative positions in lthe furnace `structure and relatively to each other during the operation of the furnace, while still I \permitting an easy and quick removal of anyv damaged refractory plate and its replacement by a new plate whenever this becomes necessary.

Various modifications may be made in the device embodying Vmy invention without departing from the spirit and scope rameau independent of said walls for maintaining' them in proper operative positions relatively to each other.

2. In an electric furnace, in combination, av plurality of walls enclosing a furnace chamber, a plurality of relatively thin refractory plates constituting the lining of said chamber, and a refractory member out of contact with said walls for interlocking the thin refractory plates, said member being located between the adjacent edges of lthe plates.

o 3. In' an electric-resistance furnace, in combination, a plurality of walls enclosing )a furnace chamber, a plurality of relatively thin refractory plates constituting the lining of said chamber, the edges ofA said plates being located in spaced-apart overlapping relation and a single shaped refractory member operatively engaging one edge and one face of each of two adjacent plates to interlock the same.

4. In an electric furnace, in combination,

a plurality ofwalls enclosing a, furnace i chamber, a plurality of relatively thin -refractory plates constituting the lining of said chamber, and a plurality of relativelyl operative positions relatively to each other.

5. In an electric-resistance furnace, in combination, a plurality of walls enclosing a furnace chamber, of substantially rectangular contour in lateral cross-section, a yplurality of relatively thin refractory plates constituting a lining for the'walls of said chamber, the lateral width of saidy plates being substantially less than the lateral dimensions of said furnace chamber, and a plurality of relatively thin refractory members, of substantially Z-shape in lateral cross-section, for operatively engaging an end face andan adjacent edge portion of each of two refractoryplates for preventing lateral movement thereof.

In testimony whereof, I have hereunto subscribed my name this 20th day of February, 1922.

THOMAS A. REID. 

